Hidden environmental costs of renewable energy storage systems

The rapid expansion of energy storage technologies is emerging as both a cornerstone and a growing vulnerability in the global shift toward renewable energy, according to a new comprehensive review published in Sustainability. 

Titled “Technological Advances in Energy Storage: Environmental and Cyber Challenges, Opportunities and Threats—A Review,” the research provides a detailed assessment of how modern storage systems are evolving from simple infrastructure tools into complex, digitally integrated assets with far-reaching environmental and geopolitical implications.

Energy storage becomes backbone of renewable transition, but complexity grows

Energy storage has moved from a supporting role to a key pillar of modern energy systems. The study highlights that global storage capacity, excluding pumped hydro, surged from just 9 GWh in 2017 to over 170 GWh in 2024, reflecting the accelerating demand for flexibility in power systems dominated by solar and wind generation.

This rapid growth is driven by the inherent intermittency of renewable energy sources. Solar and wind output fluctuate based on weather and seasonal patterns, making storage systems essential for balancing supply and demand. Technologies such as lithium-ion batteries, pumped hydro storage, and thermal storage now play a critical role in stabilizing grids, reducing reliance on fossil fuel backup, and improving overall energy efficiency.

The research categorizes storage technologies into five major classes: electrochemical, mechanical, thermal, chemical (Power-to-X), and electrical systems. Each serves a distinct function depending on the time scale of energy storage needs, from milliseconds in grid stabilization to seasonal balancing in hydrogen-based systems.

Lithium-ion batteries dominate short-duration storage due to their high efficiency of up to 95 percent and long cycle life. Flow batteries, while less energy-dense, offer durability exceeding 10,000 cycles, making them suitable for longer-duration applications. Mechanical systems such as pumped hydro remain the most mature large-scale solution, with operational lifetimes spanning decades and efficiencies between 70 and 85 percent.

Newer technologies like Power-to-X are gaining traction for long-term storage by converting electricity into hydrogen or synthetic fuels. These systems enable sector coupling across electricity, transport, and industry, but their efficiency and environmental benefits depend heavily on energy sources and system integration.

The study makes clear that no single technology can meet all system requirements. Instead, the future lies in hybrid architectures that combine multiple storage solutions to optimize performance, cost, and sustainability.

Environmental costs and material dependencies threaten sustainability goals

Energy storage technologies carry significant environmental burdens, particularly during production. The study finds that lithium-ion batteries, the dominant storage technology, require critical raw materials such as lithium, cobalt, nickel, and graphite, whose extraction is linked to soil degradation, water pollution, and high carbon emissions.

Life cycle assessments reveal that battery production is the most environmentally intensive phase, with carbon footprints ranging from 60 to 120 kg of CO2-equivalent per kWh of capacity. By contrast, pumped hydro systems have much lower lifecycle emissions, highlighting stark differences across technologies.

Water use emerges as another major concern. Lithium extraction from brine deposits can consume up to 2000 liters of water per kilogram, placing pressure on already water-scarce regions, particularly in South America.

The study points to alternative technologies such as sodium-ion batteries, which rely on more abundant materials and offer lower environmental impact. However, these systems are still in earlier stages of development and face scalability challenges.

Recycling is identified as a critical pathway to reduce environmental pressures. Advanced hydrometallurgical processes can recover up to 95 percent of key metals from spent batteries, while emerging direct recycling methods aim to reuse cathode materials without full chemical breakdown.

The concept of second-life battery applications is also gaining traction. Batteries retired from electric vehicles can retain up to 90 percent of their capacity and be repurposed for stationary storage, extending their lifecycle and reducing raw material demand. However, the study notes that recycling systems remain unevenly developed and economically dependent on battery chemistry and market conditions. As demand for storage continues to surge, the lack of mature recycling infrastructure could become a bottleneck for sustainable growth.

Cyber threats emerge as hidden environmental risk in digital energy systems

The review finds a growing intersection between cyber security and environmental risk in energy storage systems. As storage infrastructure becomes increasingly digitized, integrating battery management systems, cloud platforms, and grid interfaces, it also becomes more vulnerable to cyber attacks.

The study outlines several attack scenarios, including false data injection attacks, ransomware, and manipulation of system parameters. These attacks can disrupt operations, disable safety mechanisms, and in extreme cases trigger thermal runaway events in batteries, leading to fires and toxic emissions.

False data injection attacks, for example, can alter sensor readings such as temperature or state of charge, preventing safety systems from activating. This can result in overheating and the release of hazardous gases, creating direct environmental damage.

Similarly, denial-of-service attacks targeting cooling systems can escalate thermal risks, while ransomware incidents can delay emergency responses and prolong system downtime. The study highlights that these digital threats can indirectly lead to material losses, increased emissions, and environmental contamination.

Real-world incidents in the broader energy sector illustrate the potential scale of disruption. Cyber attacks on wind farms and gas infrastructure have demonstrated how digital vulnerabilities can compromise physical operations, raising concerns about similar risks in battery storage systems.

To address these challenges, the study calls for a layered cyber security approach, including network segmentation, multi-factor authentication, anomaly detection systems, and adherence to international standards such as IEC 62443. It emphasizes that cyber resilience must be treated as a core component of sustainability, not merely a technical issue.

Supply chain concentration and policy gaps add systemic risk

The study also highlights geopolitical risks associated with the global supply chain for critical materials. The production and processing of lithium, cobalt, and graphite are highly concentrated in a few regions, particularly China and the Democratic Republic of Congo.

This concentration creates vulnerabilities to trade disruptions, political instability, and price volatility, which could delay energy storage deployment and increase costs. At the same time, environmental impacts are often outsourced to resource-rich regions, raising concerns about uneven global sustainability outcomes.

Policy frameworks are evolving to address these challenges, but gaps remain. Regulatory barriers, unclear market classifications, and complex permitting processes continue to hinder investment in energy storage. While new policies in regions such as the European Union aim to support storage deployment, the study notes that harmonized and adaptive regulations are still needed.